The invention relates to a method of laterally supporting a steam generator in a nuclear power plant and, more particularly, to a method of supporting a steam generator originally supported with hydraulic snubbers.
A steam generator operatively connected with a pressurized water nuclear reactor by hot leg and cold leg piping must be able to withstand very large thermal forces as the system operates between room temperatures of about 70.degree. F. during outages and temperatures of up to about 500.degree. F. or more during power operation. Hydraulic snubbers are employed to laterally support a steam generator and to resist the loading forces. These snubbers allow very slow extension and retraction as the system thermally grows and contracts. Generally speaking, plants are designed such that the reactor vessels are fixed and the steam generators are allowed to float up to about one and a half inch or more. Hydraulic snubbers are essentially large bore piston assemblies connected with hydraulic fluid reservoirs. These snubbers have both sides of the piston communicating with the hydraulic fluid reservoirs to damp lateral movement of the snubber piston and, therefore, the steam generator. U.S. Pat. Nos. 4,940,025; 4,688,628; 4,583,584 and 3,771,499 are incorporated by this reference for their descriptions of the structures of steam generators and hydraulic and mechanical snubbers.
Since the early 1980s, the nuclear power industry has attempted to reduce the number of steam generator snubbers because they tend to be very expensive to maintain, inspect and test. The industry's heretofore unattained goal has been to entirely eliminate the use of hydraulic snubbers. However, the industry has been only able to reduce the number of snubbers required to support the steam generators. In addition, the snubbers are very large and radioactive and cannot be easily removed nor can they be simply left in the containments around the steam generators because available containment space is so limited.